A needle may need to be inserted into a part of a human body for many medical purposes. For example, needles are used for placing a catheter, for administrating drugs into certain parts of a human body, or for drawing blood or fluid from blood vessels or cavities. For an epidural anesthesia, a needle needs to be inserted into a narrow epidural space to place a catheter. To be inserted into the epidural space, the needle is typically held directly by one or two human hands, and then inserted into a human patient's back. After the needle is inserted into the interspinous ligament through the skin of the human patient, it is usually advanced about one millimeter in each attempt of advancement. Each attempt of advancement is followed by a loss of resistance technique to identify if the needle enters the epidural space. After the needle is inserted into the epidural space, a catheter is inserted through the needle into the epidural space followed by removal of the needle. A drug can be given through the catheter, which remains in the epidural space during epidural anesthesia.
It is not easy to hold the needle directly with a person's hands, such as with a physician's hands. Since the epidural space is very narrow, the needle can be unintentionally advanced through the epidural space into the subarachnoid space, even into the spinal cord, due to sudden movement of the patient or too much advancement of the needle. The side effect of headache may develop if the needle is inserted through the epidural space into the subarachnoid space. It is critical to hold the needle and control the advancement of the needle to avoid advancing the needle through the epidural space into the subarachnoid space or the spinal cord.
To draw blood or fluid from a human's blood vessels or cavities, a needle is held directly by one or two hands of a person, such as a physician. It is not easy to hold the needle directly and control advancement of the needle, especially when the patient is not cooperative.
A depth controller for an epidural needle, referred to in U.S. published patent application no. 20010047151 A1, incorporated by reference herein, discloses a device for holding a syringe and an epidural needle with a needle wing, and controlling the advancement of the epidural needle insertion. That device includes a screw that can block the advancement of the epidural needle to prevent over-advancement. However, it is easy to advance the epidural needle together with the device itself forward and unintentionally over-advance the epidural needle. It is not easy to hold that device, since there is no handle.